Investigating the rate of reaction between Hydrochloric acid and magnesium

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 Investigating the rate of reaction between Hydrochloric acid and magnesium

Planning

                I am investigating the rate of reaction between HCl and Mg. I will change the concentration of my acid and see how this effects the rate of reaction.

        In this experiment I predict that the higher the concentration of the acid the quicker the rate of reaction will occur. This is because if the concentration is high there will be more acid molecules in a smaller space this means more collusions will take place resulting in the rate of reaction increasing.

        As magnesium is a group two metal it is quite reactive as it reacts with water. When a metal (Mg) reacts with an acid (HCl) it forms a salt (MgCl) and hydrogen. So here is the equation for this experiment:

        Mg + 2HCl = MgCl + H

        A reaction occurs when molecules collide with each other. However they need a certain amount of force to be able to react this is called activation energy. In my experiment I am investigating with different concentrations of acid . I predicted that the higher the concentration the quicker the reaction would take place. Here are some diagrams showing why:

   

   Low concentration                                        High concentration        

        acid

        If a piece of magnesium is dropped into the low concentration of acid it will collide will less molecules than if it was in the high concentration of acid. This is called the collusion theory.

        The concentration is not the only way to alter the rate of reaction. As you can also use temperature, surface area, ph of the solution and I also could have added catalysts. Temperature affects the rate of reaction because the heat gives molecules more kinetic energy. This means they move more quickly so there will be more collusion. These collusions will also occur with a greater force therefore this will increase the chance of a successful reaction. Catalysts are chemicals that weaken the chemical bonds so they can be broken down more easily. Surface area effects a reaction as if you cut a cube in half you will have 2 more sides. This means there will be more successful collusions as the molecules have a greater chance of colliding.

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        If this is to be a fair test I will have to control all of these variables. I will do this by keeping the temperature at 20 C and I will use the same thickness of magnesium ribbon. I will also keep the ph level the same by not adding any acid or alkalise to the solution.

        To make this experiment safe I will wear goggles. Also if I happen to spill any acid or and other substance I will wipe it up straight away.

The independent variable I have chosen is the concentration. I will get different ...

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